My software assumes 2 degrees of refraction and uses the sun's upper limb
for sunrise and sunset.
This causes the center of the sun to actually be 2.25 degrees below the
horizon at sunrise and sunset. Computing moon rise and moon set was much
more difficult because the moon is much more of a moving target. I have
watched sunset many times and checked my results. They always seem quite
good but I round everything off to the nearest minute.
Carl Moreschi N4PY
Franklinton, NC
----- Original Message -----
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
To: "John Graves" <jhgraves@gis.net>
Cc: <tentec@contesting.com>
Sent: Sunday, March 16, 2003 4:14 PM
Subject: Re: [TenTec] Equinox Day
> I think my software is looking at the upper limb appearing at sunset and
> disappearing at sunset. I tested mostly sunset, since sunrise is when I
> sleep best.
>
> Still the greatest uncertainty is from the unknown effects of atmosphere
> on refraction. The necessary data simply does not exist until the
> instant it occurs.
>
> 73, Jerry, K0CQ
> --
> Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
> Reproduction by permission only.
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